genetics
razib | November 26, 2007Several years ago Oprah Winfrey asked Tiger Woods what he would say to people who say that when they look him they see a black man. The issue was that some African Americans objected to Woods' contention that he was multiracial, Cablinasian, which reflected the fact that he was ancestrally 1/2 Asian, 1/4 African, 1/8 European and 1/8 Native American. Woods is also a Therevada Buddhist by religion, taking after his Thai nationality (though mixed-race) mother, so one can argue he is quite Asian culturally. I know many people who frankly disagree with Winfrey's assessment, that is, that Woods…
razib | November 20, 2007Targeted discovery of novel human exons by comparative genomics:
Here we describe a genome-wide effort, carried out as part of the Mammalian Gene Collection (MGC) project, to identify human genes not yet in the gene catalogs. Our approach was to produce gene predictions by algorithms that rely on comparative sequence data but do not require direct cDNA evidence, then to test predicted novel genes by RT-PCR. We have identified 734 novel gene fragments (NGFs) containing 2188 exons with, at most, weak prior cDNA support. These NGFs correspond to an estimated 563 distinct genes, of which >160…
razib | November 19, 2007The most common emails I receive are about hair and eye color, and of these the most frequent source seems to be from individuals in interracial relationships. Quite often they are curious as to the possible outcome of their offspring's phenotype. Sometimes they wonder why their offspring looks the way he or she does. On one disturbing occasion someone was appealing to me to clear up the suspicion of non-paternity because of the unexpected outcome of the offspring's appearance! Today I received this email:
I have a 19 month old son who is very light skinned, blond hair and blue eyes. My…
razib | November 18, 2007Technology dramatically speeds gene mapping. A short little piece which repeats the standard mantras; faster, cheaper and better. The Human Genome Project was proof of principle. Right now, with all the stuff that is starting to bubble up around personal genomics it looks like we're at a technological and social point of no return, the second derivative is positive, the the rate of change is increasing. Hsien-Hsien is going to have to start getting a bit more selective about what she blogs about since the sample space of upon which the commentary is based will start to rapidly increase in…
razib | November 17, 2007My Genome, Myself: Seeking Clues in DNA:
For as little as $1,000 and a saliva sample, customers will be able to learn what is known so far about how the billions of bits in their biological code shape who they are. Three companies have already announced plans to market such services, one yesterday.
Offered the chance to be among the early testers, I agreed, but not without reservations. What if I learned I was likely to die young? Or that I might have passed on a rogue gene to my daughter? And more pragmatically, what if an insurance company or an employer used such information against me in…
razib | November 17, 2007A few weeks ago I reported some research that seemed to show a relationship between a gain in IQ due to breastfeeding and a particular genetic variant. Looks like I spoke too soon. p-ter has the goods:
The fact that they have a measure of maternal IQ but don't directly include it in the published multiple regression suggests that they tried it, but didn't like the results. They didn't include parental phenotype in any of their previous studies, but there, at least, there was some functional evidence linking the polymorphism and the phenotype. Here, there's nothing. Considering the fact…
gregladen | November 17, 2007Today, deCODE genetics announced the launch of their consumer genotyping service, deCODEme. deCODEme is the first personal genomics company to launch, and will provide sequencing information about 1 million SNPs for the introductory price of $985. The service has two components:
[source]
From deCODEme (Man, I'm siCK of these miXEDcase companynames.):
"Through your subscription to deCODEme, you can learn what your DNA says about your ancestry, your body -traits such as hair and eye color- as well as whether you may have genetic variants that have been associated with higher or lower than…
razib | November 16, 2007Simpler mode of inheritance of transcriptional variation in male Drosophila melanogaster:
Sexual selection drives faster evolution in males. The X chromosome is potentially an important target for sexual selection, because hemizygosity in males permits accumulation of alleles, causing tradeoffs in fitness between sexes. Hemizygosity of the X could cause fundamentally different modes of inheritance between the sexes, with more additive variation in males and more nonadditive variation in females. Indeed, we find that genetic variation for the transcriptome is primarily additive in males but…
razib | November 14, 2007I've discussed heritability quite a bit on this weblog. Over the past 5 years of blogging on genetic topics this is the #1 issue I've been attempting to nail into the heads of readers because it is a concept which is critical in correctly modeling the world around us. It isn't an idea which is in common circulation, as evidenced by the common assertions in the press which go along the lines of "the trait is half genetic" or "the trait is mostly genetic," after reporting the heritability estimate from the original research. Part of the problem is that heritability emerges out of the…
razib | November 11, 2007On page 380 of Population Genetics and Microevolutionary Theory I stumbled onto some interesting data from the 1970s. The paper was Admixture Studies and the Detection of Selection , and its aim was to gage the extent of white ancestry within black populations. They generated a measure, M, for the extent of ancestry across a range of loci like so:
change in allele frequency between African Americans and West Africans
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change in allele frequency between Europeans and West Africans
In short M relates the ratio of the genetic…
razib | November 10, 2007Just a note, as I've read most of it now I'm starting to think that Alan Templeton's Population Genetics and Microevolutionary Theory is an excellent complement to R.A. Fisher's classic The Genetical Theory of Natural Selection. Fisher's prose is dense, and sometimes it is a bit much to extract clarity from his somewhat turgid early 20th century style. The wordiness which I complained about earlier serves Templeton well in clarifying concepts Fisher introduced such as average excess, a, and average effect, α, but did not elaborate upon in great detail.1 Where Fisher might define a concept…
razib | November 9, 2007So, check out this retarded post at the Huntington Post, Goodbye Selfish-Gene: A New Upheaval in the Science of Human Behavior:
Plain talk: The Darwinian prop of the lone cowboy rugged conservative bundle of selfish genes has now been pulled out from under the cowboy and the lone cowboy has suddenly collapsed into a mumbling baffled cartoon.
Humans are pack animals. We live and die in herds. The group provides the individual with the means of physical and psychological survival. We need the group as much as the group needs us. It's a fair trade that's been evolving for millions of years.
The…
razib | November 9, 2007Due to positive mentions from readers and friends I finally got Alan Templeton's Population Genetics and Microevolutionary Theory. I've read a few chapters and skimmed through much of the book, and my current take is that it's a bit too wordy in the exposition. I'd have preferred that there be more technical boxes and a more thorough scattering of compact formalisms. That being said, Templeton is a clear writer and the text is pretty penetrable (I enjoyed the coverage of quantitative genetics especially). Also, he didn't seem to take a kitchen-sink approach, a few themes came in for…
gregladen | November 9, 2007
... well, OK, maybe that is a slight exaggeration.
You know about giardia. Giardia intestinalis. It causes a nasty gut infection, and you get it by drinking water pretty much anywhere in the US (potentially). It is very hard to get rid of.
Giardia adapt to immune system attacks (of their host) in a way that passes that adaptation down to their offspring without genes. It is a Lamarkian process. Giardia have no mitochondria, yet many of the genes known to be in mitochondria in eukaryotes are found in the giardian nucleus. So, ancestral giardia probably had mitochondria, but all those…
razib | November 8, 2007Genetics Has A Role In Determining Sexual Orientation In Men, Further Evidence:
In other research, Witelson and research associate Debra Kigar, had found that left-handers have a larger region of the posterior corpus callosum -- the thick band of nerve fibres connecting the two hemispheres of the brain -- than right handers.
This raised the hypothesis for the current study -- whether the anatomy of the brain of the sub-group of right-handed homosexual men is similar to that of left-handers.
They found that the posterior part of the corpus callosum is larger in homosexual than heterosexual men…
grrlscientist | November 6, 2007tags: researchblogging.org, supermouse, Phosphoenolpyruvate Carboxykinase, PEPCK-C, glucose metabolism
Like a Lance Armstrong equivalent among ordinary mice, a group of American scientists report that they altered a single gene involved in glucose metabolism in a mouse and discovered that this genetically altered mouse demonstrates remarkable athletic abilities. For example, this supermouse runs 20 meters per minute for five hours or more without stopping -- a distance of 3.7 miles (6 kilometers)!
"They are metabolically similar to Lance Armstrong biking up the Pyrenees. They utilize…
razib | November 5, 2007Moderation of breastfeeding effects on the IQ by genetic variation in fatty acid metabolism:
...Breastfed children attain higher IQ scores than children not fed breast milk, presumably because of the fatty acids uniquely available in breast milk. Here we show that the association between breastfeeding and IQ is moderated by a genetic variant in FADS2, a gene involved in the genetic control of fatty acid pathways. We confirmed this gene-environment interaction in two birth cohorts, and we ruled out alternative explanations of the finding involving gene-exposure correlation, intrauterine growth…
grrlscientist | November 4, 2007tags: Mendel's Garden, blog carnival
The November issue of Mendel's Garden is now available for you to enjoy. This issue was written so as to read like the narrative of a soccer game (it also includes a streaming video of philosophers playing soccer).
razib | November 1, 2007William Saletan has a piece up over at Slate, Jewgenics, which covers his reactions to a talk (you can view it online) sponsored by AEI around Jon Entine's book Abraham's Children: Race, Identity, and the DNA of the Chosen People. I've read the book, though I don't have time to listen to the talk right now. But I wanted to offer a quick perspective on one point in Saletan's piece:
According to Entine, the rate of Jewish "outbreeding"--procreating with non-Jews--is half a percent. That's the lowest rate of any population in the world today....
First, I don't know if that is the lowest rate…